CS378 - Mobile Computing

1. CS378 - Mobile Computing More UI

2. Concrete Example • Tip Calculator • What kind of layoutto use? • Widgets: • TextView • EditText • SeekBar

3. TextViews

4. EditText All but top EditText are uneditable Alternative? TextViews?

5. SeekBar

6. Layout • TableLayout row 0 row 1 row 2 row 3 row 4 row 5

7. Layout Attributes • android:background • #RGB, #ARGB, #RRGGBB, #AARRGGBB • can place colors in res/values/colors.xml

8. Color Resources • Good Resource / W3C colors • http://tinyurl.com/6py9huk

9. StretchColumns • columns 0 indexed • columns 1, 2, 3 stretch to fill layout width • column 0 wide as widest element, plus any padding for that element

10. Initial UI • Done via some Drag and Drop, Outline view, and editing XML • Demo outline view • properties

11. Changes to UI • Outline multiple select properties • all TextViews' textColor set to black #000000 • change column for %DD labels • use center gravity for components

12. Changes to UI • change bill total and seekbar to span more columns • gravity and padding for text in column 0 • align text with seekBar • set seekBar progress to 18 • set seekBar focusable to false - keep keyboard on screen

13. Changes to UI • Prevent Editing in EditText • focusable, long clickable, and cursor visible properties to false • Set text in EditText to 0.00 • Change weights to 1 to spread out

14. Functionality • onCreate instance variables assigned to components found via ids • update standard percents:

15. Functionality - Saving State • onSaveInstance • save BillTotal and CustomPercent to the Bundle • check for these in onCreate

16. Functionality Responding to SeekBar • customSeekBarListener instance variable • Of type OnSeekBarChangeListener

17. Create an Anonymous Inner Class • Class notified when seek bar changed and program updates custom tip and total amount • must register with the seekBar instance variable in onCreate.

18. Functionality - Total EditText • Another anonymous inner class • implement onTextChangedto converts to double and call update methods • register with EditText for total in onCreate()!

20. Constraining Input • EditText from tip calculator • input was numberDecimal • Use InputFilter to constrain input • Several built in filters such as AllCaps and LengthFilter

21. Custom Input Filter • InputFilter has one method: public CharSequence filter(CharSequencesource, int start, int end, Spanned dest, int dstart, int dend) { • replace dstart to dend in dest with new text, start to end of source

23. dialogs

24. Dialogs - Old Way • Dialogs from tutorials were cut and paste • Implementing Dialogs demonstrates evolution of Android SDK • legacy approach has Activity manage its own Dialogs • created, initialized, updated, and destroyed using Activity class call back methods

25. Dialogs - New Way • Android evolving from smartphone OSto smart device OS • API level 11 (Android 3.0, the tablet release) introduced Fragments • A fragment represents a behavior or a portion of a UI in an Activity • like a sub activity • multiple fragments combined in multi-pane UI • reuse fragments in multiple activities

26. Fragments

27. Dialogs as Fragments • Dialogs are special type of Fragment • managed by the FragmentManager class • still part of an activity, but lifecycle not managed by the Activity • life cycle issues of Dialogs as Fragments will be more difficult to deal with • must save state and restore instance

28. Types of Dialogs • Used to organize information and react to user events without creating a whole new activity • Old Dialogs: • Dialog, AlertDialog, DatePickerDialog, TimePickerDialog, ProgressDialog • New Dialogs: • DialogFragment

29. Sample Dialogs

30. Legacy Approach • Dialog defined in Activity it is used • Activity maintains a pool of Dialogs • showDialog() method displays Dialog • dismissDialog() method used to stop showing a Dialog • in tutorial, when we have difficulty • removeDialog removes from pool

31. Legacy Approach - Steps • Define unique indentifier for the Dialog in Activity (constants) • implement onCreateDialog method, returns Dialog of appropriate type

32. onCreateDialog

33. Dialog Steps - Legacy Approach • implement onPrepareDialog() if necessary • if necessary to update dialog each time it is displayed • for example, a time picker, update with the current time • launch dialog with showDialog() • in tutorials done when a menu or action bar menu item selected • could launch Dialogs for other reasons

34. Alert Dialogs • Most common type • Title, Content Area, Action buttons (up to 3) • Content area could be message, list, seekbar, etc. • set positive, set negative, set neutral

35. Custom Dialogs • AlertDialog very flexible, but you can create CustomDialogs • Create a layout

36. Custom Dialogs • from onCreateDialog

37. Custom Dialog • Simple dialogs are dismissed with the back button dialog title

38. Dialogs - Fragment Method • Decouple Dialogs from the Activity • good SE approach? • TicTacToe UI is almost 500 lines long! • Implement a class that is a subclass of DialogFragment • DifficultyFragment • Send info to newInstance method (current difficulty, listener for updates) • onCreateDialog now in DifficultyFragment

39. DifficultyFragment

40. DifficultyFragment - onCreateDialog

41. Using DifficultyFragment • In AndroidTicTacToe create a listener to pass to the newInstance method • create and show Dialog as part of onOptionsItemSelected()

42. DifficultyListener

43. Using Fragments • Fragments added in API level 11, Android 3.0, the tablet release • Developers behind Android think fragments are so important that can be used in pre API 11 builds using the Android Support Library Froyo and Gingerbread pre API 11

44. Android Support Library (ASL) • add library to project and application • android.support.v4.app.DialogFragment • for example • instead of android.app.DialogFragment • ASL does not supportaction bar in earlierversions of API

45. Fragment Lifecycle • Demo Tic Tac Toe with old style Dialog and Fragment Dialog • Alter orientation - result? http://developer.android.com/guide/components/fragments.html